Magnetic storage system read back signals suffer from several types of distortion including frequency instability (caused by rotation or media speed instability), non-additive media noise, additive system noise, low frequency distortion from a read back amplifier, and amplitude modulation (caused by inhomogeneous media, disk media runout, read head fly height dynamics, and tracking dynamics). Simple analysis of read back signals where they are displayed on oscilloscopes or composed into histograms using a time interval analyzer do not allow the distortion sources to be removed or separately analyzed. It would be beneficial to be able to analyze read back signals and determine the magnitude of each distortion and somehow separate the different sources for distortions.